JacobianPropagatorConverter.java
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*
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* Unless required by applicable law or agreed to in writing, software
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package org.orekit.propagation.conversion;
import java.util.List;
import org.hipparchus.analysis.MultivariateVectorFunction;
import org.hipparchus.linear.ArrayRealVector;
import org.hipparchus.linear.MatrixUtils;
import org.hipparchus.linear.RealMatrix;
import org.hipparchus.linear.RealVector;
import org.hipparchus.optim.nonlinear.vector.leastsquares.MultivariateJacobianFunction;
import org.hipparchus.util.Pair;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitMessages;
import org.orekit.orbits.OrbitType;
import org.orekit.propagation.MatricesHarvester;
import org.orekit.propagation.SpacecraftState;
import org.orekit.propagation.numerical.NumericalPropagator;
import org.orekit.propagation.sampling.OrekitStepHandler;
import org.orekit.propagation.sampling.OrekitStepInterpolator;
import org.orekit.time.AbsoluteDate;
import org.orekit.utils.PVCoordinates;
import org.orekit.utils.ParameterDriver;
import org.orekit.utils.ParameterDriversList;
import org.orekit.utils.TimeSpanMap.Span;
/** Propagator converter using the real Jacobian.
* @author Pascal Parraud
* @since 6.0
*/
public class JacobianPropagatorConverter extends AbstractPropagatorConverter {
/** Numerical propagator builder. */
private final NumericalPropagatorBuilder builder;
/** Simple constructor.
* @param builder builder for adapted propagator, it <em>must</em>
* be configured to generate {@link OrbitType#CARTESIAN} states
* @param threshold absolute threshold for optimization algorithm
* @param maxIterations maximum number of iterations for fitting
*/
public JacobianPropagatorConverter(final NumericalPropagatorBuilder builder,
final double threshold,
final int maxIterations) {
super(builder, threshold, maxIterations);
if (builder.getOrbitType() != OrbitType.CARTESIAN) {
throw new OrekitException(OrekitMessages.ORBIT_TYPE_NOT_ALLOWED,
builder.getOrbitType(), OrbitType.CARTESIAN);
}
this.builder = builder;
}
/** {@inheritDoc} */
protected MultivariateVectorFunction getObjectiveFunction() {
return point -> {
final NumericalPropagator propagator = builder.buildPropagator(point);
final ValuesHandler handler = new ValuesHandler();
propagator.getMultiplexer().add(handler);
final List<SpacecraftState> sample = getSample();
propagator.propagate(sample.get(sample.size() - 1).getDate().shiftedBy(10.0));
return handler.value;
};
}
/** {@inheritDoc} */
protected MultivariateJacobianFunction getModel() {
return point -> {
final NumericalPropagator propagator = builder.buildPropagator(point.toArray());
final JacobianHandler handler = new JacobianHandler(propagator, point.getDimension());
propagator.getMultiplexer().add(handler);
final List<SpacecraftState> sample = getSample();
propagator.propagate(sample.get(sample.size() - 1).getDate().shiftedBy(10.0));
return new Pair<>(handler.value, handler.jacobian);
};
}
/** Handler for picking up values at sample dates.
* <p>
* This class is heavily based on org.orekit.estimation.leastsquares.MeasurementHandler.
* </p>
* @since 11.1
*/
private class ValuesHandler implements OrekitStepHandler {
/** Values vector. */
private final double[] value;
/** Number of the next measurement. */
private int number;
/** Index of the next component in the model. */
private int index;
/** Simple constructor.
*/
ValuesHandler() {
this.value = new double[getTargetSize()];
}
/** {@inheritDoc} */
@Override
public void init(final SpacecraftState initialState, final AbsoluteDate target) {
number = 0;
index = 0;
}
/** {@inheritDoc} */
@Override
public void handleStep(final OrekitStepInterpolator interpolator) {
while (number < getSample().size()) {
// Consider the next sample to handle
final SpacecraftState next = getSample().get(number);
// Current state date
final AbsoluteDate currentDate = interpolator.getCurrentState().getDate();
if (next.getDate().compareTo(currentDate) > 0) {
return;
}
final PVCoordinates pv = interpolator.getInterpolatedState(next.getDate()).getPVCoordinates(getFrame());
value[index++] = pv.getPosition().getX();
value[index++] = pv.getPosition().getY();
value[index++] = pv.getPosition().getZ();
if (!isOnlyPosition()) {
value[index++] = pv.getVelocity().getX();
value[index++] = pv.getVelocity().getY();
value[index++] = pv.getVelocity().getZ();
}
// prepare handling of next measurement
++number;
}
}
}
/** Handler for picking up Jacobians at sample dates.
* <p>
* This class is heavily based on org.orekit.estimation.leastsquares.MeasurementHandler.
* </p>
* @since 11.1
*/
private class JacobianHandler implements OrekitStepHandler {
/** Values vector. */
private final RealVector value;
/** Jacobian matrix. */
private final RealMatrix jacobian;
/** State size (3 or 6). */
private final int stateSize;
/** Matrices harvester. */
private final MatricesHarvester harvester;
/** Number of the next measurement. */
private int number;
/** Index of the next Jacobian component in the model. */
private int index;
/** Simple constructor.
* @param propagator propagator
* @param columns number of columns of the Jacobian matrix
*/
JacobianHandler(final NumericalPropagator propagator, final int columns) {
this.value = new ArrayRealVector(getTargetSize());
this.jacobian = MatrixUtils.createRealMatrix(getTargetSize(), columns);
this.stateSize = isOnlyPosition() ? 3 : 6;
this.harvester = propagator.setupMatricesComputation("converter-partials", null, null);
}
/** {@inheritDoc} */
@Override
public void init(final SpacecraftState initialState, final AbsoluteDate target) {
number = 0;
index = 0;
}
/** {@inheritDoc} */
@Override
public void handleStep(final OrekitStepInterpolator interpolator) {
while (number < getSample().size()) {
// Consider the next sample to handle
final SpacecraftState next = getSample().get(number);
// Current state date
final AbsoluteDate currentDate = interpolator.getCurrentState().getDate();
if (next.getDate().compareTo(currentDate) > 0) {
return;
}
fillRows(index, interpolator.getInterpolatedState(next.getDate()),
builder.getOrbitalParametersDrivers());
// prepare handling of next measurement
++number;
index += stateSize;
}
}
/** Fill up a few Jacobian rows (either 6 or 3 depending on velocities used or not).
* @param row first row index
* @param state spacecraft state
* @param orbitalParameters drivers for the orbital parameters
*/
private void fillRows(final int row,
final SpacecraftState state,
final ParameterDriversList orbitalParameters) {
// value part
final PVCoordinates pv = state.getPVCoordinates(getFrame());
value.setEntry(row, pv.getPosition().getX());
value.setEntry(row + 1, pv.getPosition().getY());
value.setEntry(row + 2, pv.getPosition().getZ());
if (!isOnlyPosition()) {
value.setEntry(row + 3, pv.getVelocity().getX());
value.setEntry(row + 4, pv.getVelocity().getY());
value.setEntry(row + 5, pv.getVelocity().getZ());
}
// Jacobian part
final RealMatrix dYdY0 = harvester.getStateTransitionMatrix(state);
final RealMatrix dYdP = harvester.getParametersJacobian(state);
for (int k = 0; k < stateSize; k++) {
int column = 0;
for (int j = 0; j < orbitalParameters.getNbParams(); ++j) {
final ParameterDriver driver = orbitalParameters.getDrivers().get(j);
if (driver.isSelected()) {
jacobian.setEntry(row + k, column++, dYdY0.getEntry(k, j) * driver.getScale());
}
}
if (dYdP != null) {
for (int j = 0; j < dYdP.getColumnDimension(); ++j) {
final String name = harvester.getJacobiansColumnsNames().get(j);
for (final ParameterDriver driver : builder.getPropagationParametersDrivers().getDrivers()) {
for (Span<String> span = driver.getNamesSpanMap().getFirstSpan(); span != null; span = span.next()) {
if (name.equals(span.getData())) {
jacobian.setEntry(row + k, column++, dYdP.getEntry(k, j) * driver.getScale());
}
}
}
}
}
}
}
}
}